2 # For a description of the syntax of this configuration file,
3 # see Documentation/kbuild/kconfig-language.txt.
17 config LOCKDEP_SUPPORT
20 config STACKTRACE_SUPPORT
23 config HAVE_LATENCYTOP_SUPPORT
26 config RWSEM_GENERIC_SPINLOCK
29 config RWSEM_XCHGADD_ALGORITHM
32 config ARCH_HAS_ILOG2_U32
36 config ARCH_HAS_ILOG2_U64
40 config GENERIC_HWEIGHT
46 config GENERIC_TIME_VSYSCALL
49 config GENERIC_CLOCKEVENTS
63 config GENERIC_LOCKBREAK
66 depends on SMP && PREEMPT
72 config VIRT_CPU_ACCOUNTING
75 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
78 mainmenu "Linux Kernel Configuration"
82 select USE_GENERIC_SMP_HELPERS if SMP
83 select HAVE_SYSCALL_WRAPPERS
84 select HAVE_FUNCTION_TRACER
85 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
86 select HAVE_FTRACE_MCOUNT_RECORD
87 select HAVE_DYNAMIC_FTRACE
88 select HAVE_DEFAULT_NO_SPIN_MUTEXES
91 select HAVE_KRETPROBES
92 select HAVE_KVM if 64BIT
93 select HAVE_ARCH_TRACEHOOK
94 select INIT_ALL_POSSIBLE
98 source "kernel/Kconfig.freezer"
102 comment "Processor type and features"
104 source "kernel/time/Kconfig"
109 Select this option if you have a 64 bit IBM zSeries machine
110 and want to use the 64 bit addressing mode.
117 bool "Symmetric multi-processing support"
119 This enables support for systems with more than one CPU. If you have
120 a system with only one CPU, like most personal computers, say N. If
121 you have a system with more than one CPU, say Y.
123 If you say N here, the kernel will run on single and multiprocessor
124 machines, but will use only one CPU of a multiprocessor machine. If
125 you say Y here, the kernel will run on many, but not all,
126 singleprocessor machines. On a singleprocessor machine, the kernel
127 will run faster if you say N here.
129 See also the SMP-HOWTO available at
130 <http://www.tldp.org/docs.html#howto>.
132 Even if you don't know what to do here, say Y.
135 int "Maximum number of CPUs (2-64)"
138 default "32" if !64BIT
139 default "64" if 64BIT
141 This allows you to specify the maximum number of CPUs which this
142 kernel will support. The maximum supported value is 64 and the
143 minimum value which makes sense is 2.
145 This is purely to save memory - each supported CPU adds
146 approximately sixteen kilobytes to the kernel image.
149 bool "Support for hot-pluggable CPUs"
154 Say Y here to be able to turn CPUs off and on. CPUs
155 can be controlled through /sys/devices/system/cpu/cpu#.
156 Say N if you want to disable CPU hotplug.
159 bool "IEEE FPU emulation"
162 This option is required for IEEE compliant floating point arithmetic
163 on older S/390 machines. Say Y unless you know your machine doesn't
167 bool "Kernel support for 31 bit emulation"
169 select COMPAT_BINFMT_ELF
171 Select this option if you want to enable your system kernel to
172 handle system-calls from ELF binaries for 31 bit ESA. This option
173 (and some other stuff like libraries and such) is needed for
174 executing 31 bit applications. It is safe to say "Y".
176 config SYSVIPC_COMPAT
178 depends on COMPAT && SYSVIPC
185 config S390_SWITCH_AMODE
186 bool "Switch kernel/user addressing modes"
188 This option allows to switch the addressing modes of kernel and user
189 space. The kernel parameter switch_amode=on will enable this feature,
190 default is disabled. Enabling this (via kernel parameter) on machines
191 earlier than IBM System z9-109 EC/BC will reduce system performance.
193 Note that this option will also be selected by selecting the execute
194 protection option below. Enabling the execute protection via the
195 noexec kernel parameter will also switch the addressing modes,
196 independent of the switch_amode kernel parameter.
199 config S390_EXEC_PROTECT
200 bool "Data execute protection"
201 select S390_SWITCH_AMODE
203 This option allows to enable a buffer overflow protection for user
204 space programs and it also selects the addressing mode option above.
205 The kernel parameter noexec=on will enable this feature and also
206 switch the addressing modes, default is disabled. Enabling this (via
207 kernel parameter) on machines earlier than IBM System z9-109 EC/BC
208 will reduce system performance.
210 comment "Code generation options"
213 prompt "Processor type"
217 bool "S/390 model G5 and G6"
220 Select this to build a 31 bit kernel that works
221 on all S/390 and zSeries machines.
224 bool "IBM eServer zSeries model z800 and z900"
226 Select this to optimize for zSeries machines. This
227 will enable some optimizations that are not available
228 on older 31 bit only CPUs.
231 bool "IBM eServer zSeries model z890 and z990"
233 Select this enable optimizations for model z890/z990.
234 This will be slightly faster but does not work on
235 older machines such as the z900.
240 Select this to enable optimizations for IBM System z9-109, IBM
241 System z9 Enterprise Class (z9 EC), and IBM System z9 Business
242 Class (z9 BC). The kernel will be slightly faster but will not
243 work on older machines such as the z990, z890, z900, and z800.
246 bool "IBM System z10"
248 Select this to enable optimizations for IBM System z10. The
249 kernel will be slightly faster but will not work on older
250 machines such as the z990, z890, z900, z800, z9-109, z9-ec
256 bool "Pack kernel stack"
258 This option enables the compiler option -mkernel-backchain if it
259 is available. If the option is available the compiler supports
260 the new stack layout which dramatically reduces the minimum stack
261 frame size. With an old compiler a non-leaf function needs a
262 minimum of 96 bytes on 31 bit and 160 bytes on 64 bit. With
263 -mkernel-backchain the minimum size drops to 16 byte on 31 bit
264 and 24 byte on 64 bit.
266 Say Y if you are unsure.
269 bool "Use 8kb for kernel stack instead of 16kb"
270 depends on PACK_STACK && 64BIT && !LOCKDEP
272 If you say Y here and the compiler supports the -mkernel-backchain
273 option the kernel will use a smaller kernel stack size. The reduced
274 size is 8kb instead of 16kb. This allows to run more threads on a
275 system and reduces the pressure on the memory management for higher
276 order page allocations.
278 Say N if you are unsure.
281 bool "Detect kernel stack overflow"
283 This option enables the compiler option -mstack-guard and
284 -mstack-size if they are available. If the compiler supports them
285 it will emit additional code to each function prolog to trigger
286 an illegal operation if the kernel stack is about to overflow.
288 Say N if you are unsure.
291 int "Size of the guard area (128-1024)"
293 depends on CHECK_STACK
296 This allows you to specify the size of the guard area at the lower
297 end of the kernel stack. If the kernel stack points into the guard
298 area on function entry an illegal operation is triggered. The size
299 needs to be a power of 2. Please keep in mind that the size of an
300 interrupt frame is 184 bytes for 31 bit and 328 bytes on 64 bit.
301 The minimum size for the stack guard should be 256 for 31 bit and
305 bool "Emit compiler warnings for function with broken stack usage"
307 This option enables the compiler options -mwarn-framesize and
308 -mwarn-dynamicstack. If the compiler supports these options it
309 will generate warnings for function which either use alloca or
310 create a stack frame bigger than CONFIG_WARN_STACK_SIZE.
312 Say N if you are unsure.
314 config WARN_STACK_SIZE
315 int "Maximum frame size considered safe (128-2048)"
317 depends on WARN_STACK
320 This allows you to specify the maximum frame size a function may
321 have without the compiler complaining about it.
323 config ARCH_POPULATES_NODE_MAP
326 comment "Kernel preemption"
328 source "kernel/Kconfig.preempt"
330 config ARCH_SPARSEMEM_ENABLE
332 select SPARSEMEM_VMEMMAP_ENABLE
333 select SPARSEMEM_VMEMMAP
334 select SPARSEMEM_STATIC if !64BIT
336 config ARCH_SPARSEMEM_DEFAULT
339 config ARCH_SELECT_MEMORY_MODEL
342 config ARCH_ENABLE_MEMORY_HOTPLUG
346 config ARCH_ENABLE_MEMORY_HOTREMOVE
351 comment "I/O subsystem configuration"
354 tristate "QDIO support"
356 This driver provides the Queued Direct I/O base support for
359 To compile this driver as a module, choose M here: the
360 module will be called qdio.
365 tristate "Support for CHSC subchannels"
367 This driver allows usage of CHSC subchannels. A CHSC subchannel
368 is usually present on LPAR only.
369 The driver creates a device /dev/chsc, which may be used to
370 obtain I/O configuration information about the machine and
371 to issue asynchronous chsc commands (DANGEROUS).
372 You will usually only want to use this interface on a special
373 LPAR designated for system management.
375 To compile this driver as a module, choose M here: the
376 module will be called chsc_sch.
383 bool "Builtin IPL record support"
385 If you want to use the produced kernel to IPL directly from a
386 device, you have to merge a bootsector specific to the device
387 into the first bytes of the kernel. You will have to select the
391 prompt "IPL method generated into head.S"
395 Select "tape" if you want to IPL the image from a Tape.
397 Select "vm_reader" if you are running under VM/ESA and want
398 to IPL the image from the emulated card reader.
408 source "fs/Kconfig.binfmt"
410 config FORCE_MAX_ZONEORDER
415 bool "Show crashed user process info"
417 Say Y to print all process fault locations to the console. This is
418 a debugging option; you probably do not want to set it unless you
419 are an S390 port maintainer.
422 bool "Pseudo page fault support"
424 Select this option, if you want to use PFAULT pseudo page fault
425 handling under VM. If running native or in LPAR, this option
426 has no effect. If your VM does not support PFAULT, PAGEEX
427 pseudo page fault handling will be used.
428 Note that VM 4.2 supports PFAULT but has a bug in its
429 implementation that causes some problems.
430 Everybody who wants to run Linux under VM != VM4.2 should select
434 bool "VM shared kernel support"
436 Select this option, if you want to share the text segment of the
437 Linux kernel between different VM guests. This reduces memory
438 usage with lots of guests but greatly increases kernel size.
439 Also if a kernel was IPL'ed from a shared segment the kexec system
441 You should only select this option if you know what you are
442 doing and want to exploit this feature.
445 tristate "Cooperative memory management"
447 Select this option, if you want to enable the kernel interface
448 to reduce the memory size of the system. This is accomplished
449 by allocating pages of memory and put them "on hold". This only
450 makes sense for a system running under VM where the unused pages
451 will be reused by VM for other guest systems. The interface
452 allows an external monitor to balance memory of many systems.
453 Everybody who wants to run Linux under VM should select this
457 bool "/proc interface to cooperative memory management"
460 Select this option to enable the /proc interface to the
461 cooperative memory management.
464 bool "IUCV special message interface to cooperative memory management"
465 depends on CMM && (SMSGIUCV=y || CMM=SMSGIUCV)
467 Select this option to enable the special message interface to
468 the cooperative memory management.
471 bool "Unused page notification"
473 This enables the notification of unused pages to the
474 hypervisor. The ESSA instruction is used to do the states
475 changes between a page that has content and the unused state.
478 bool "Linux - VM Monitor Stream, base infrastructure"
481 This provides a kernel interface for creating and updating z/VM APPLDATA
482 monitor records. The monitor records are updated at certain time
483 intervals, once the timer is started.
484 Writing 1 or 0 to /proc/appldata/timer starts(1) or stops(0) the timer,
485 i.e. enables or disables monitoring on the Linux side.
486 A custom interval value (in seconds) can be written to
487 /proc/appldata/interval.
489 Defaults are 60 seconds interval and timer off.
490 The /proc entries can also be read from, showing the current settings.
493 tristate "Monitor memory management statistics"
494 depends on APPLDATA_BASE && VM_EVENT_COUNTERS
496 This provides memory management related data to the Linux - VM Monitor
497 Stream, like paging/swapping rate, memory utilisation, etc.
498 Writing 1 or 0 to /proc/appldata/memory creates(1) or removes(0) a z/VM
499 APPLDATA monitor record, i.e. enables or disables monitoring this record
503 The /proc entry can also be read from, showing the current settings.
505 This can also be compiled as a module, which will be called
509 tristate "Monitor OS statistics"
510 depends on APPLDATA_BASE
512 This provides OS related data to the Linux - VM Monitor Stream, like
513 CPU utilisation, etc.
514 Writing 1 or 0 to /proc/appldata/os creates(1) or removes(0) a z/VM
515 APPLDATA monitor record, i.e. enables or disables monitoring this record
519 This can also be compiled as a module, which will be called
522 config APPLDATA_NET_SUM
523 tristate "Monitor overall network statistics"
524 depends on APPLDATA_BASE && NET
526 This provides network related data to the Linux - VM Monitor Stream,
527 currently there is only a total sum of network I/O statistics, no
529 Writing 1 or 0 to /proc/appldata/net_sum creates(1) or removes(0) a z/VM
530 APPLDATA monitor record, i.e. enables or disables monitoring this record
534 This can also be compiled as a module, which will be called
537 source kernel/Kconfig.hz
540 bool "s390 hypervisor file system support"
541 select SYS_HYPERVISOR
544 This is a virtual file system intended to provide accounting
545 information in an s390 hypervisor environment.
548 bool "kexec system call"
550 kexec is a system call that implements the ability to shutdown your
551 current kernel, and to start another kernel. It is like a reboot
552 but is independent of hardware/microcode support.
555 bool "zfcpdump support"
559 Select this option if you want to build an zfcpdump enabled kernel.
560 Refer to <file:Documentation/s390/zfcpdump.txt> for more details on this.
563 bool "s390 guest support for KVM (EXPERIMENTAL)"
564 depends on 64BIT && EXPERIMENTAL
567 select VIRTIO_CONSOLE
569 Select this option if you want to run the kernel as a guest under
570 the KVM hypervisor. This will add detection for KVM as well as a
571 virtio transport. If KVM is detected, the virtio console will be
575 bool "Enable seccomp to safely compute untrusted bytecode"
579 This kernel feature is useful for number crunching applications
580 that may need to compute untrusted bytecode during their
581 execution. By using pipes or other transports made available to
582 the process as file descriptors supporting the read/write
583 syscalls, it's possible to isolate those applications in
584 their own address space using seccomp. Once seccomp is
585 enabled via /proc/<pid>/seccomp, it cannot be disabled
586 and the task is only allowed to execute a few safe syscalls
587 defined by each seccomp mode.
601 source "drivers/Kconfig"
605 source "arch/s390/Kconfig.debug"
607 source "security/Kconfig"
609 source "crypto/Kconfig"
613 source "arch/s390/kvm/Kconfig"